Applied Biochemistry and Biotechnology, Vol.169, No.4, 1188-1196, 2013
Selective Lead Adsorption by Recombinant Escherichia coli Displaying a Lead-Binding Peptide
A highly specific lead-binding peptide ThrAsnThrLeuSerAsnAsn was displayed on Escherichia coli, and lead adsorption characteristics of the recombinant bacteria were investigated. Cell surface-displayed peptide was expressed under the control of an arabinose promoter using outer membrane protein C (OmpC(t)) as an anchoring motif. The optimal induction period and arabinose concentration for the expression of peptide-fused OmpC(t) were determined to be 2 h and 0.001 g/L, respectively. Selective adsorption of Pb2+ onto recombinant cells was verified with individual or combinatory use of four metal ions, Pb2+, Ni2+, Co2+, and Cu2+; the amount of bound Pb2+ onto the biosorbents was significantly higher than the other metal ions. The adsorption isotherm of recombinant cells for Pb2+ followed the Langmuir isotherm with a maximum adsorption loading (q (max)) of 526 mu mol/g dry cell weight.